Do you think this idea could work for capping the oil leak?

You would first have to neutralize the pressure of the oil and gas with recirculating drilling mud which is how they normally set cement plugs in the well and was what they were doing when the accident occurred. Top kill was an attempt to do just that again but with all the damage they were unable to recirculate the mud so once they had a limited supply with which to neutralize the pressure. Note that the cement they use is an expanding foam cement so it is in fact your balloon idea. The pressure is just way too much to try inserting anything without first using drilling mud, deflated or not. Nice thought but if that would've worked then top kill would've worked.

I'm not sure that idea would be very effective because balloons pop when there is too much pressure and i think the balloon would pop before anyone got the chance to cover it up with a "top cap" plug. However may be I'm wrong. i just picture the whole thing being WAY too messy if it does go wrong:)

Big Red would laugh his head off at this one he made hundreds thousands of $dollars risking his life dealing with such things this would have been used ages ago the pressure is to great to put soft things that expand with a rod into a raging hole anyway nice try people make millions£ thinking like you do keep it up Dyson etc had better look out!

Well I'm sure he wasn't talking about a birthday balloon LMAO. They could use a synthetic material (I have no accurate knowledge on this topic) that could semi stretch, but mainly just fill up and act like a 'balloon'. Honestly, is a latex balloon gonna really work people? Lol (I was talking about the other people who answered this question)

Water and oil pressure is so strong the balloon will break or pop so the idea will not work. I think it is good for people to try and think of a solution. BP could have prepared for this calamity but chose not to because of their greed.

I have a detailed plan for saving our pristine coastlands although it's too late for some of them.

i dnt think it would work but at least ur trying to think of an solution while ppl sit on thier buts..many places that the oil seeping into their wetlands arent getting help from the govnt n take matters into their own hands..like the one place was using vaccums to suck out the oil but wut other choice they have if the govt wont help

i think they should bring the troops back home..the hell wiht iraq and have the military pitch in with the cleanup not just the coast guard

Well - write it in to Obama at the White House. I'm sure they'd love to hear about any idea at this point. This one is really bad!

sure... know any balloons that can handle a half a million lbs of pressure?? soon as we find one we are good to go!